The announcement by Stephen Curry, one of pro basketball’s biggest stars, that he had signed a major endorsement deal with the Chinese sportswear brand Li-Ning raises the profile of a company that has lacked the cachet of Western brands like Nike or Adidas. The agreement, which Mr. Curry announced on Monday, is set to give the N.B.A. star access to China’s enormous consumer base, while offering Li-Ning its biggest ever inroad into the U.S. sportswear market. Under the partnership, Mr. Curry, the N.B.A.’s three-point record-holder and point guard for the…